Closure devices are known in manifold shapes and are usually produced from a plastic material, they can also be produced from other materials, e.g. metals, however. A base element typically comprises a device for fixing the base element to an opening of the container, for example to a bottle neck, wherein particularly an internal thread can be provided, so that the closure device can be screwed onto the bottle neck.
A spout preferably extends from the base element, particularly a dome-shaped spout, which can also be enclosed by the mouth of the person drinking when drinking from the container for example.
Particularly in the cases in which liquids to which carbonic acid has been added can be accommodated in the container, an increased pressure can develop in the container. Even in the case of liquids to which carbonic acid has not been added, a pressure difference can be built up, for example if the container is transported at different altitudes, as is the case during mountain hiking for example. Even weather changes can already lead to corresponding pressure differences. In the case of opening the closure device, that is to say when opening the lid, it can therefore come to pass that the pressure compensation takes place very suddenly, wherein the medium stored in the container might undesirably flow out of the container.
It is an object of the present invention to provide an improved closure device, in the case of which, particularly this undesirable flowing out of the product located in the container is prevented or at least the amount of the medium flowing out is remarkably reduced.
This object is achieved by means of a closure device according to the claims.